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Man page of pathconf
pathconf
Section: System Calls (2)
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NAME
pathconf, fpathconf - Retrieve file implementation characteristics
SYNOPSIS
#include <unistd.h>
long pathconf(
const char *path,
int name);
long fpathconf(
int filedes,
int name);
STANDARDS
Interfaces documented on this reference page conform to industry
standards as follows:
fpathconf(),
pathconf(): POSIX.1, XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
PARAMETERS
Specifies the pathname.
If the final component of
path
is a symbolic link, it will be traversed and filename resolution will
continue.
Specifies an open file descriptor.
Specifies the configuration attribute to be queried.
DESCRIPTION
The fpathconf() and pathconf() functions provide a method
for an application to determine the current value of a configurable limit
or option (variable) that is associated with a file or directory.
For pathconf(),
the path parameter points to the pathname of a file or directory.
Read, write, or execute permission of the
named file is not required, but all directories in the path leading
to the file must be searchable.
The following is a list of the system variables
whose values are returned by pathconf() and fpathconf()
and the symbolic constants (shown in parentheses) that are the
corresponding values used for the name parameter.
The variables come from either the limits.h
or unistd.h header file and the symbolic constants
are defined in unistd.h.
The maximum number of links to the file.
-
If path or filedes
refers to a directory, the value returned applies to the directory
itself.
-
The maximum number of bytes in a canonical input line.
-
The association of this variable name with the specified file
is guaranteed only when path or filedes refers to a terminal file.
The minimum number of bytes for which space is available in an input queue;
therefore, the maximum number of bytes a portable application may require
to be typed as input before reading them.
-
The association of this variable name with the specified file
is guaranteed only when path or filedes refers to a terminal file.
The maximum number of bytes in a filename (not including
a terminating null).
-
If path or filedes refers to a directory,
the value returned applies to filenames within the directory.
-
The association of this variable name with the specified file
is guaranteed only when path or filedes refers to a directory.
The maximum number of bytes in a pathname (including
a terminating null).
-
If path or filedes refers to a directory,
the value returned is the maximum length of a
relative pathname when the specified directory is the working
directory.
-
The association of this variable name with the specified file
is guaranteed only when path or filedes refers to a directory.
The maximum number of bytes guaranteed to be atomic when writing
to a pipe.
-
If path refers to a FIFO, or filedes refers to a pipe or FIFO,
the value returned applies to the referenced object. If path or
filedes refers to a directory, the value returned applies to any FIFO
that exists or can be created within the directory.
-
The association of this variable name with the specified file is not
guaranteed if path or filedes refers to any other type of file.
The use of chown() is restricted to a process with appropriate
privileges, and to changing the group ID of a file only to the effective
group ID of the process or to one of its supplementary group IDs.
-
If the path or filedes parameter refers to a directory,
the value returned applies to any files (other than directories) that
exist or can be created within the directory.
Returns 0 (zero) if supplying a component name longer
than allowed by NAME_MAX will cause an error. Returns 1 if long
component names are truncated.
-
If path or filedes refers to a directory,
the value returned applies to filenames within the directory.
-
The association of this variable name with the specified file
is guaranteed only when path or filedes refers to a directory.
A character value used to disable terminal special characters.
-
The association of this variable name with the specified file
is guaranteed only when path or filedes refers to a terminal file.
RETURN VALUES
Upon successful completion,
the pathconf() or fpathconf() function returns
the specified parameter.
If name is an invalid value, both
pathconf() and fpathconf() return -1 and errno is set
to indicate the error.
If the variable corresponding to name has no limit for the path
or file descriptor, both pathconf() and
fpathconf() return -1 without changing errno.
ERRORS
If the pathconf() function fails,
errno
may be set to the following value:
Search permission is denied for a component of the path prefix.
[XPG4-UNIX] Too many links were encountered in translating
a pathname.
The name parameter specifies an unknown or
inapplicable characteristic.
[Digital] The
path
argument is an invalid address.
The length of the
path string exceeds PATH_MAX or a pathname component
is longer than NAME_MAX.
-
[XPG4-UNIX] Pathname resolution of a symbolic link produced an
intermediate result whose length exceeds PATH_MAX.
The named file does not exist or the path argument points to an
empty string.
A component of the path prefix is not a directory.
If the fpathconf() function fails,
errno
may be set to the following value:
The name parameter specifies an unknown or
inapplicable characteristic.
The filedes argument is not a valid file descriptor.
[Digital] The named file has been revoked.
RELATED INFORMATION
Standards:
standards(5)
delim off
Index
- NAME
-
- SYNOPSIS
-
- STANDARDS
-
- PARAMETERS
-
- DESCRIPTION
-
- RETURN VALUES
-
- ERRORS
-
- RELATED INFORMATION
-
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Time: 02:40:17 GMT, October 02, 2010